I should have also mentioned that in addition to the explicit tick values,
you can also include explicit viewWindow: { min and max } so you can get
the effect of the 'pretty' mode by expanding the bounds yourself. The
algorithm for 'pretty' mode is to expand the minValue to maxValue range by
10%. Hope that helps.
On Mon, Aug 12, 2013 at 9:28 PM, Daniel LaLiberte <[email protected]>wrote:
> Hi Luke,
>
> The algorithm that google charts uses to determine the axis range and
> intervals between ticks is not as straightforward as what you have shown,
> since it generally tries several different strategies until it finds one
> that works "best".
>
> One alternative you might consider is that now you can provide a explicit
> array of tick values that will be used in google charts, so you can arrange
> that you will use the same ticks in your image charts. This is done by
> using a 'ticks' option within one of the axes structures, where the value
> of the option is an array of tick values, or instead of just the values,
> you can specify the formatted representation along with the value. So, for
> example, you might use this:
>
> vAxis: {
> ticks: [ {v: 0, f: 'zero'}, 10, 20, 30, 40, 50 ]
> }
>
> One difference to be aware of is that the 'pretty' mode of the
> viewWindowMode will not be used with the explicit ticks, and it will
> instead behave as if you have specified 'explicit' and use the lowest and
> highest values in the array of ticks as the bounds. We are considering how
> to combine this with the 'pretty' mode in a future version.
>
>
>
> On Mon, Aug 12, 2013 at 7:59 PM, Luke Bellamy <[email protected]>wrote:
>
>> Hi,
>> I'm using google charts (basic combo chart) on a web site. Awesome, no
>> problem with that. I wish to put this into a PDF. So what I did was using
>> the deprecated image charts to generate an image using the same data and
>> making them look the same. Works great.
>>
>> My issue is that the vertical axis intervals, min, and max are not the
>> same. I understand why and I prefer the 'pretty' axis scaling in google
>> charts. So I thought I would come up with an algorithm myself using the min
>> and max from the data to come up with the range and intervals. This is for
>> the old image charts. Works very well, but in a couple of scenarios I can
>> see it's not EXACTLY the same, although close. Note that these are very
>> basic charts so I'm not doing anything fancy. It would just be nice if they
>> looked identical.
>>
>> My question is, can I find the axis range and interval algorithm from
>> google charts somewhere? I did see the google visualization java code
>> available but code not find what I was after.
>> Here is the basic bit of code I have been tweaking in JAVA for image
>> charts to mirror the axis algorithm of google charts.
>>
>> // Take the Max/Min of all data values in all graphs
>> var totalMax = 345;
>> var totalMin = -123;
>>
>> // Figure out the largest number (positive or negative)
>> var biggestNumber = Math.max(Math.abs(totalMax),Math.abs(totalMin));
>>
>> // Round to an exponent of 10 appropriate for the biggest number
>> var roundingExp = Math.floor(Math.log(biggestNumber) / Math.LN10);
>> var roundingDec = Math.pow(10,roundingExp);
>>
>> // Round your max and min to the nearest exponent of 10
>> var newMax = roundHalfUp(totalMax/roundingDec)*roundingDec;
>> var newMin = roundHalfDown(totalMin/roundingDec)*roundingDec;
>>
>> // Determine the range of your values
>> var range = newMax - newMin;
>>
>> // Define the number of gridlines (default 5)
>> var gridlines = 5;
>>
>> // Determine an appropriate gap between gridlines
>> var interval = range / (gridlines - 1);
>>
>> // Round that interval up to the exponent of 10
>> var newInterval = roundHalfUp(interval/roundingDec)*roundingDec;
>>
>> // Re-round your max and min to the new interval
>> var finalMax = Math.ceil(totalMax/newInterval)*newInterval;
>> var finalMin = Math.floor(totalMin/newInterval)*newInterval;
>>
>>
>>
>> Thankyou,
>> Luke
>>
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>>
>>
>
>
>
> --
> Daniel LaLiberte <https://plus.google.com/100631381223468223275?prsrc=2>
> - 978-394-1058
> [email protected] <[email protected]> 562D 5CC, Cambridge MA
> [email protected] <[email protected]> 9 Juniper Ridge
> Road, Acton MA
>
--
Daniel LaLiberte <https://plus.google.com/100631381223468223275?prsrc=2> -
978-394-1058
[email protected] <[email protected]> 562D 5CC, Cambridge MA
[email protected] <[email protected]> 9 Juniper Ridge
Road, Acton MA
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